Single injection of clenbuterol into newly hatched chicks decreases abdominal fat pad weight in growing broiler chickens

The aim of the current study was to examine the effects of clenbuterol injection into newly hatched chicks on both the abdominal fat pad tissue weight and the skeletal muscle weight during subsequent growth. Twenty‐seven 1‐day‐old chicks were divided into two groups, receiving either a single intraperitoneal (i.p.) injection of clenbuterol (0.1 mg/kg body weight) or phosphate‐buffered saline (PBS). Body weight gain, feed intake and feed conversion ratio were not affected by clenbuterol injection during the 5‐week experimental period, while the abdominal fat pad tissue weight of the clenbuterol‐injected chicks was lower than that of the control chicks at 5 weeks post‐injection. Plasma non‐esterified fatty acid concentrations were significantly increased in the clenbuterol‐injected chicks, while plasma triacylglycerol concentrations did not differ. Additionally, the enzymatic activity of fatty acid synthase was lower in the liver of the clenbuterol‐injected chicks. Conversely, the skeletal muscle weights were not affected by clenbuterol injection. These results suggest that a single clenbuterol injection into 1‐day‐old chicks decreases the abdominal fat pad tissue weight, but may not affect skeletal muscle weights during growth. © 2015 Japanese Society of Animal Science     

Effects of chitin degradation products N-acetylglucosamine and N,Nʹ-diacetylchitobiose on chitinase activity and bacterial community structure in an incubated upland soil

ABSTRACT

Chitin, which is the polymer of N-acetylglucosamine (GlcNAc) linked by β1,4 glycoside bonds, has been reported as a soil amendment to mitigate plant soil diseases, increasing the population of chitin-degrading bacteria, and chitinolytic enzymatic activity in the soil. In some chitin-degrading bacteria, whose chitinolytic systems have been intensively studied, the chitin degradation product N,N?-diacetylchitobiose {(GlcNAc)₂} induces expression of genes for chitinases whereas GlcNAc does not. To evaluate the effects of these mono- and disaccharides on the population and activity of chitinolytic bacteria in soil, we investigated the chitinolytic enzyme activity and bacterial community structure in an incubated upland soil supplemented with GlcNAc or (GlcNAc)₂. The added GlcNAc and (GlcNAc)₂ (2 mg g^?1) were consumed within 1 d when incubated at 25°C. Chitinase activity was induced by (GlcNAc)₂ and chitin after 1-d and 7-d incubation, respectively, but not by GlcNAc. N-acetylglucosaminidase (GlcNAcase) activity was induced by GlcNAc but was lower than those by (GlcNAc)₂ and chitin. Amplicon sequencing analysis targeting 16S rRNA genes demonstrated that both GlcNAc and (GlcNAc)₂ significantly increased the rate of the order Bacillales, but the compositions of Bacillales differed from each other: the family Planococcaceae significantly increased in either GlcNAc- or (GlcNAc)₂-added soil, but the genera Bacillus and Paenibacillus were increased mainly by GlcNAc and (GlcNAc)₂, respectively. The family Streptomycetaceae of the order Actinomycetales was significantly increased by (GlcNAc)₂ and chitin, but GlcNAc did not. Thus, GlcNAc and (GlcNAc)₂, which were promptly consumed in the incubated soil, indicated partly similar but distinctive effects on chitinolytic enzyme activity and bacterial communities. Both aminosugars increased GlcNAcase activity and the population size of Planococcaceae. GlcNAc increased Bacillus. Chitinase activity and the populations of Paenibacillus and Streptomycetaceae, a number of strains of which are known as potent chitin-degraders, were increased by (GlcNAc)₂, but not by GlcNAc.     

X-irradiation Removes Endogenous Primordial Germ Cells (PGCs) and Increases Germline Transmission of Donor PGCs in Chimeric Chickens

Primordial germ cells (PGCs) are embryonic precursors of germline cells with potential applications in genetic conservation, transgenic animal production and germline stem cell research. These lines of research would benefit from improved germline transmission of transplanted PGCs in chimeric chickens. We therefore evaluated the effects of pretransplant X-irradiation of recipient embryos on the efficacy of germline transmission of donor PGCs in chimeric chickens. Intact chicken eggs were exposed to X-ray doses of 3, 6 and 9 Gy (dose rate = 0.12 Gy/min) after 52 h of incubation. There was no significant difference in hatching rate between the 3-Gy-irradiated group and the nonirradiated control group (40.0 vs. 69.6%), but the hatching rate in the 6-Gy-irradiated group (28.6%) was significantly lower than in the control group (P<0.05). No embryos irradiated with 9 Gy of X-rays survived to hatching. X-irradiation significantly reduced the number of endogenous PGCs in the embryonic gonads at stage 27 in a dose-dependent manner compared with nonirradiated controls. The numbers of endogenous PGCs in the 3-, 6- and 9-Gy-irradiated groups were 21.0, 9.6 and 4.6% of the nonirradiated control numbers, respectively. Sets of 100 donor PGCs were subsequently transferred intravascularly into embryos irradiated with 3 Gy X-rays and nonirradiated control embryos. Genetic cross-test analysis revealed that the germline transmission rate in the 3-Gy-irradiated group was significantly higher than in the control group (27.5 vs. 5.6%; P<0.05). In conclusion, X-irradiation reduced the number of endogenous PGCs and increased the germline transmission of transferred PGCs in chimeric chickens.     

Increased expression of NOR‐1 mRNA in the skeletal muscles of cold‐exposed neonatal chicks

Nuclear receptor subfamily 4, group A (NR4A) subgroup orphan receptors are rapidly induced by various physiological stimuli and have been suggested to regulate oxidative metabolism and muscle mass in mammalian skeletal muscle. The results showed that the NR4A subgroup orphan receptor, NOR‐1 (NR4A3), was acutely increased in skeletal muscles of neonatal chicks in response to short‐term cold exposure. The increased NOR‐1 gene expression was concomitant with cold‐induced changes in gene expression of both myostatin and proliferator‐activated receptor‐gamma coactivator‐1 (PGC‐1α), and the increase in skeletal muscle mass. These observations suggest that NOR‐1 might play a role in controlling skeletal muscle growth in cold‐exposed neonatal chicks.     

Ontogenic and morphological study of gonadal formation in genetically-modified sex reversal XYPOS mice

Mammalian sexual fate is determined by the presence or absence of sex determining region of the Y chromosome (Sry) in the “bipotential” gonads. Recent studies have demonstrated that both male and female sexual development are induced by distinct and active genetic pathways. Breeding the Y chromosome from Mus m. domesticus poschiavinus (POS) strains into C57BL/6J (B6J) mice (B6J-XY^POS) has been shown to induce sex reversal (75%: bilateral ovary, 25%: true hermaphrodites). However, our B6N-XY^POS mice, which were generated by backcrossing of B6J-XY^POS on an inbred B6N-XX, develop as males (36%: bilateral testis with fertility as well as bilateral ovary (34%), and the remainder develop as true hermaphrodites. Here, we investigated in detail the expressions of essential sex-related genes and histological features in B6N-XY^POS mice from the fetal period to adulthood. The onsets of both Sry and SRY-box 9 (Sox9) expressions as determined spatiotemporally by whole-mount immunohistochemistry in the B6N-XY^POS gonads occurred 2–3 tail somites later than those in B6N-XY^B6 gonads, but earlier than those in B6J-XY^POS, respectively. It is possible that such a small difference in timing of the Sry expression underlies testicular development in our B6N-XY^POS. Our study is the first to histologically show the expression and ectopic localization of a female-related gene in the XY^POS testes and a male-related gene in the XY^POS ovaries. The results from these and previous experiments indicate that the interplay between genome variants, epigenetics and developmental gene regulation is crucial for testis development.     

The combined effect of clothianidin and environmental stress on the behavioral and reproductive function in male mice

Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling cause of honeybee colony collapse disorder, which is damaging crop production that requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for neonicotinoids with lower levels than those of insects; there is thus rising concern about unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the effects of neonicotinoids would be enhanced under a chronic stressed condition, which is known to alter the expression of targets of neonicotinoids, i.e., neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day), for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test, although the locomotor activities were not affected, the anxiety-like behaviors of the mice were elevated by both CTD and stress. The present study demonstrates that the behavioral and reproductive effects of CTD become more serious in combination with environmental stress, which may reflect our actual situation of multiple exposure.     

Method for Estimating the Content of the Chloroform-Extractable Green Fraction (CEGF) in HCl-DMSO Extract of Soils

Chloroform-extractable green fraction (CEGF) was detected in the supernatant obtained by alkali precipitation from the HCI-dimethylsulfoxide (DMSO) extract of Pg-rich soil. In the alkaline solution, the color of CEGF was green and CEGF showed strong Pg-like absorption bands. Ultraviolet and visible (UV-VIS) spectral analysis and gel chromatography on Sephadex G-50 were performed to compare several properties between CEGF and Pg. CEGF, which was purified by gel chromatography on Bio-Beads SX-1, displayed strong absorption bands at 609, 562, 445 and 280 inn in the alkaline solution. These absorption bands were almost similar to those of Pg. Furthermore, the UV-VIS spectrum of CEGF in the organic solvents showed a similar characteristic pattern of 4,9-dihydroxyperylene-3,10-quinone (DHPQ), which was considered to be a chromophore of Pg. Based on the results of gel chromatography on Sephadex G-50, CEGF mainly consisted of two fractions, corresponding to the G₂ and G₃ fractions of Pg. These results indicated that the method for extracting CEGF from Pg-rich soil in the present study was easy and selective and that CEGF was one of the components of, or a closely related substance to Pg. A colorimetric method for the estimation of the CEGF content in soils was developed. The calibration curve of CEGF was linear over a wide range of contents from 2.75 to 220 mg L⁻¹. The CEGF content in twelve samples of various soils was examined. CEGF was detected in all the soil sampled (5 orders) including three samples (3 orders) where Pg was not detected, and the content ranged from 0.07 to 1.66 g kg⁻¹ (dry soil). Therefore, the method for estimating the CEGF content in soils developed in the present study was found to be suitable for various soil orders and it was assumed that CEGF occurred in various soil orders.     

Effects of hypoxia on principal prey and growth of flathead flounder Hippoglossoides dubius in Funka Bay, Japan

ABSTRACT:   Effects of hypoxia on the principal prey and growth of flathead flounder Hippoglossoides dubius were studied in Funka Bay. Of the three dominant year-classes that occurred in recent years, the 1995 year-class was small in total length at age ≥ 3 and low in condition factor at age ≥ 2. Ophiuroids (almost Ophiura sarsi ), which were the dominant prey in the 1980s, were of little importance and instead, crustaceans such as mysids, natant decapods and pelagic amphipods, bivalves and fish were important prey items for H. dubius in 2000–2001. In addition, the feeding intensity of H. dubius in 2000–2001 was lower than that in the 1980s. These facts are closely related to a reduction of prey abundance, particularly ophiuroids. It seems that the hypoxia that occurred in the central part of the bay during the summer and autumn of 1995–1997 caused the poor food supply and low growth rate at ages 2–4 of the 1995 year-class.     

A rice FRD3-like (OsFRDL1) gene is expressed in the cells involved in long-distance transport

We identified four putative AtFRD3-like genes (OsFRDL) in the rice genome that exhibited 39.1 to 56.7% amino acid sequence similarities to Arabidopsis FRD3. Of these, we cloned three OsFRDL genes from a cDNA library prepared from iron-deficient rice roots: OsFRDL1, OsFRDL2, and OsFRDL3. OsFRDL1 was expressed weakly in Fe-sufficient roots, and slight expression was induced in the roots of Fe-deficient plants. OsFRDL2 was expressed constitutively in both roots and leaves, and Fe deficiency reduced its expression in leaves. OsFRDL3 was expressed in leaves, but not in roots; Fe deficiency induced slight expression in leaves. An OsFRDL1-sGFP fusion protein was localized in the plasma membrane in onion epidermal cells. The promoter GUS analysis showed that OsFRDL1 was localized in the cells involved in long-distance transport, in both Fe-sufficient and Fe-deficient plants. Furthermore, OsFRDL1 expression was observed during the reproductive stage. These results suggest that OsFRDL1 is a transporter that resides in the plasma membrane of cells involved in long-distant transport.